Apparatus for drying paper, paperboard, pulp, and the like



R. A. HAYWARD APPARATUS FOR DRYING PAPER,

Dec. 5, 1950 PAPERBQARD, PULP, AND THE LIKE Filed Sept. 2, 1947 IINVENTOR. fa/ fi /9. #4

BY yard/w (22m. 5M1 /7//0/wz A HAYWAR 2,532,910 I R. D APPARATUS FORDRYING PAPER, PAPERBOARD, PUL1, AND THE LIKE I 2 Sheets-Sheet 2 FiledSept. 2, 1947 uvmvroa.

Patented Dec. 5, 1956 anger APPARATUS FOR DRYING PAPER, PAPER- BOARD,PULP, AND THE LIKE Ralph A. Hayward, Parchment, Mich, minor to KalamazooVegetable Parchment Company,

Parchment, Mich.

Application September 2, 1947, Serial No. 771,746

Claims.

This invention relates to improvements in apparatus for drying paper,paperboard, pulp and the like.

The principal objects of this invention are:

First, to provide apparatus for drying paper pulp, paperboard or otherpaper stock which will effectively dry a web of the material and whichapparatus will be less expensive to manufacture and operate thanexisting paper drying apparatus.

Second, to provide apparatus for drying paper pulp and the like whichgreatly reduces the amount of space required and also the equipmentnecessary to complete the drying operation.

Third, to provide a novel drying roll for a paper drying machine whichmay be installed in existing paper making machinery to materiallyincrease the speed of operation and output of the machinery.

Fourth, to provide a method of drying paper pulp, paperboard or otherpaper stock which is faster than presently used methods of dryingsimilar materials.

Fifth, to provide a method for drying paper stock of various types whichmaterially increases the drying area of the paper while at the same timematerially reduces the amount of mechanical apparatus for handling thestock.

Other objects and advantages pertaining to the details and economies ofmy invention will be apparent from a consideration of the followingdescription and claims.

The drawings, of which there are two sheets, illustrate a preferred formof my drying apparatus and two examples of the application of myapparatus and method to a paper drying machine,

Fig. 1 is a fragmetary end elevational view, partially broken away icross section along the line l-l in Fig. 2, of my paper drying apparatusas installed on a conventional paper drying machine.

Fig. 2 is a fragmentary plan view of one end of the apparatus shown inFig. 1, portions of the supporting framework being broken away inhorizontal cross section.

Fig. 3 is a fragmentary cross sectional view along the line 3-3 in Fig.1 and illustrating the web of paper in operative position on my dryingapparatus.

Fig. 4 is a fragmentary cross sectional view along the line 4-4 in Fig.1 and illustrating certain details of the construction of the baiiiestructure employed therein.

Fig. 5 illustrates conventionally the application 2 of my dryingapparatus and method to a machine for d yin paperboard and the like. 1

Fig. 6 illustrates conventionally the method employing my apparatus andmethod in a machine for drying pulp stock.

At the present time it is the practice in the manufacture of. paperstock of various weights and quality. ranging from pulp stock topaperboard and thin finished paper, to forma web of the stock bywell-known manufacturing proc'-- esses which web is extremely wet andweak due to its moisture content. The web is then tion is effected byevaporation from the surfaces 1 of the web, the rolls acting merely toheat, flex and support the web during the evaporation process. As aresult, paper drying machines have been provided with a large number ofrolls and operated at relatively slow speeds to allow time for thenecessary evaporation.

It is my invention to materially reduce the number of drying rollsnecessary to effectively dry the paper stock and to increase the speedat which the web and rolls may be operated. I do this by first passingthe newly formed web of stock i its wet condition over a series ofheated rolls in the same manner as has previously been done but to raisethe temperature of the moisture in the web to 212 F. or above, as soonas possible. I then pass the web over a device'for applying a vacuum toone side of the web to draw a quantity of air through the web todisplace the moisture therein. While previous machines have encouragedthe circulation of air around the drying rolls, I can eliminate thisfeature in my initial rolls as the principal abject of the initial rollsis to raise the temperature of the web as rapidly as possible andvaporize the moisture in the web. I also prefer to provide a source ofheated air to be drawn through the web so that there is no condensationof the moisture in the web as the air is drawn therethrough by thevacuum.

Different types and grades of paper stock will of course requireslightly different methods of treatment depending upon the propertiesdesired in the finished product. Thus, in drying paper pulp where themain object is to remove as much moisture as possible for shipment ofthe pulp, the web of pulp stock may be collected immediately uponleaving my vacuum drying apparatus.

In manufacturing paperboard or finished sheet stock where certainmoisture contents are desired in the stock, it may be desirable to passthe web over a few equalizing and conditioning rolls after leaving myvacuum drying apparatus before collecting the web in its finished form.In any use of my drying method and apparatus. the effect of theapparatus is to increase the eifective drying area of the stock millionsof times, since the hot air in being drawn through the web of stockpasses over each of the individual fibres within .the stock asdistinguished from passing merely over the surface of the web.

While various methods of applying a vacuum to the paper may be devised,I prefer to employ a roll which may be installed in an existing paperdrying machine in place of any one ofthe existing rolls in that machine.In Figs. 1 to 4 I have lllustrated portions of a paper drying machinehaving a framework I and a conventional drying roll 2. My drying rollwhich replaces one of the conventional rolls is illustrated generally at3 and consists of a hollow cylindricalroll 4 having hollow end members 5secured thereto as by the bolts 6. The roll end member. 5 is shaped intoa hollow journal. portion I arranged to be supported in a bearing 8mounted on the framework l in the usual fashion. The journal portion isprovided with a rotating gland member or inner ring 9 which rotates withthe roll and roll end member '5 and fits within an outer ring In securedto the fixed vacuum pipe II.- A suitable packing gland and ring isprovided at II. The opposite end member of the roll (not shown) may beprovided with a similar vacuum connectionor may be closed so that all ofthe air is drawn through one end of the roll 4. The pipe II is connectedto any suitable vacuum pump or fan (not shown).

The body of the roll 4 defines a series of radially extending holes l3preferably countersunk as at l4 at their outer ends and the surface ofthe roll is spirally grooved to receive onehalf the thickness of aspirally wound wire' wrapper IS. The adjacent turns of the wrapper wireI5 are spaced close enough together to eifectively support the web ofpaper stock indicated I at IE, but at the same time provide passagesopening to the holes l3. Note that the under' surface of the web is thusspaced from the surface of the roll between the holes I! to provide asubstantially continuous surface open to the action of the vacuum in theroll.

In order to seal oil. the holes I3 between the entering and leavingpositions of .the web l6,

I provide a bafile, generally indicated at H, con- 7 sisting of a curvedbaflle plate 18 which is spaced radially from the surface of the rolland provided with inwardly turned flanges I9 along eachend thereof seeFig. 4). The flanges I! support curved, wood sealing blocks 20 whichslidingly engage the ends of the roll 4 to seal the ends of the baflieto the roll. The leading and trailing edges of the baflie plate It aresealed-to the surface of the roll by tapered doctor blades II which alsoserve to guide the web l6 onto and away from the vacuum roll.

In order to provide the supply of heated air to the outer surface of theweb as it passes around the vacuum roll, I provide a hood 22 extendingsubstantially around the vacuum roll between the doctor blades 21 andcompletely along the length of the vacuum roll. The hood 22 is spacedradially from the web to provide an air chame her and a conduit 23 isconnected to the hood through which hot air may be supplied from anysuitable source.

In Flg. 5 I have illustrated an installation of of my vacuum roll in aconventional drying machine i'or drying paper and paperboard in whichthe moisture content of the finished product is to be accuratelycontrolled. The conventional heating rolls are indicated at 2 and myvacuum roll is indicated at I. The pipe for applying a vacuum to-theroll is shown at H and the conduit for supplying hot air to the roll isshown at 23. In arrangement of my vacuum roll the web It is passed fromthe paper making machine 24 over a sufilcient number of initial heatingrolls 2 to raise the temperature of the web and the moisture therein to212 1''. or above, and the web is then passed around my vacuum roll aspreviously described. From my vacuum roll the web is passed around aheating roll 2A to equalize the remaining moisture content of the weband is then passed through a set of calendering or pressing rolls 2|where calendering is desired.

Fig. 6 illustrates an application of my vacuum roll 3 to a paper dryingmachine for producing pulp stock.- In'this arrangement the web I8 ispassed. around a. suitable number of initial heating rolls 2 as in Fig.5 and then around the vacuum roll 3. the pulp stock may be passedthrough pressure rolls if desired.

It should be understood that my method and apparatus has varyingapplications depending upon the weight and grade of the paper stock orpaper pulp being produced and the desired final properties of theproductproduced. The examples I have illustrated are intended to illustrate theprinciples of operation of my method and apparatusand are not intendedto define the limits of their application.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1'. A drying roll adapted to be mounted in a paper drying machinecomprising a hollow cylindrical roll member defining a plurality ofradially extending apertures opening to the outer surface thereof, andcounter-sunk at' their outer ends, the outer-surface of said roll memberbeing spirally grooved, a wrapper wire wound in said spiral groove andprojecting thereabove by one-half the thickness of said wire, the pitchof I said spiral groove and wire being slightly greater versely spacedrelationship, a hollow roll end member secured to one end of said rollmember and forming a. hollow journal adapted to be supported in saidmachine, a rotating gland member secured to the end of said Juornal, anda vacuum pipe communicating with said hollow journal and having a fixedgland cooperating. with said rotating gland member. I

2. A drying r'oll adapted to be mounted in a paper drying machinecomprising a hollow cylindrical roll member defining a plurality ofradially extending apertures opening to the outer surface thereof, theouter surface of said roll member being spirally grooved, and a wrapperwire wound in said spiral groove and projecting thereabove, the pitch ofsaid spiral groove and wire being slightly greater than the diameter ofthe wire whereby several successive turns of the wire bridge the ends ofeach of said apertures in transversely spaced relationship.

7; 3. A machine for drying paper stock compris- After leaving the vacuumroll 3' 5 ing. means for translating a web of the stock. a preliminaryheating element positioned to have said web passed in heat transferrelationship therewith and adapted to raise the temperature of said weband the moisture therein to the boiling temperature of themoisture,wal1s forming a vacuum chamber,,one of said walls beingperforated and positioned to have said web translated thereacross whileat said boiling temperature, a series of supporting elements disposed inclosely and transversely spaced relation along said perforated wall andprojecting slightly there from and bridging the perforations therein tohave linecontact with and support said web in closely spaced relation tosaid perforated wall, means for maintaining a vacuum in said chamher, ahood forming an air chamber and located on the opposite side of said webfrom said perforated wall, means for supplying heated air to said airchamber, and a second heating element positioned to have said web passedin heat transfer relationship therewith after passing said vacuumchamber.

4. In a web drying apparatus the combination of means for translating aweb to be dried, heating means for raising the temperature of themoisture content of the web to the vaporization point while the web isin motion, a rotatable suction head positioned at the rear of saidheating means, said head being provided with a plurality of suctionorifices having enlargements at the peripheral surface of the head, thehead being provided with peripheral encircling web supporting ribscertain of which extend across the orifices and constitute means forsupport- I 6 ing the web to provide circulation passages between theribs opening to the orifices, and means for supporting and guiding theweb around a substantial peripheral segment of said head.

' 5. In a web drying apparatus the combination of means for translatinga web to be dried,

means for raising the temperature of the moisture content of the web tothe vaporization point while the web is being translated and a suctionhead positioned at the rear of said heating means, said head beingprovided with a plurality of orifices having enlargements at the surfaceof the head, the head being further provided with web supporting ribscertain of which extend across the orifices and constituting means. forsupporting the web to provide circulation passages between the ribsopening to'the orifices.

i RALPH A. HAYWARD.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,000,391 Famham Aug. 15, 19111,115,808 Cessner Nov. 3, 1914 1,427,437 Breuer Aug. 29, 1922 1,664,656Berry Apr. 3, 1928 2,061,976 Merckens Nov. 24, 1936 2,091,805 Chuse Aug.31, 1937 2,174,744 Hill Oct. 3, 1939 2,199,455 Berry May 7, 19402,224,803 Standley Dec. 10, 1940 2,231,224 Russell et a1. Feb. 11, 1941

